Photographic material containing a hydrophilic colloid and a sucrose ester



United States Patent F 3,516,833 PHOTOGRAPHIC MATERIAL CONTAINING A HYDROPHILIC COLLOID AND A SUCROSE ESTER Walter Hagge and Mathieu Quaedvlieg, Leverkusen, Ru-

dolf Heusch, Cologne-Stammheim, Konrad Hebbel, Leverkusen, and Richard Schiffmann, Cologne-Flittard, Germany, assignors to Agfa Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Jan. 9, 1964, Ser. No. 336,648 Claims priority, applicatio; 1Germany, Jan. 26, 1963,

4 80 Int. Cl. G03c 1/38 US. Cl. 96-114.5 7 Claims ABSTRACT OF THE DISCLOSURE This invention relates to silver halide photographic elements having at least one layer comprising a hydrophilic colloid and a sucrose ester of an aliphatic monocarboxylic acid having at least 8 carbon atoms.

This invention relates to gelatin silver halide emulsions and emulsion layers which contain monofatty acid esters of saccharose as non-ionogenic wetting agents.

It is common practice to add surface-active agents to light-sensitive gelatin layers or photographic auxiliary layers, such as intermediate layers or protective layers, in order to ensure uniform wetting of the support or of the layer which is to be coated. The addition of such substances is necessary in order to prevent the formation of areas of insufficient adhesion or areas not covered by layers. The size of these defective areas may vary from the barely visilble to several centimeters in diameter.

Many different natural and synthetic wetting agents such as saponine, polyethylene derivatives, quaternary ammonium salts with long chained aliphatic radicals and the like have been described as additives. However, all these substances are of limited utility because of certain disadvantage; such as insufficient wetting action, deleterious effect on the light-sensitive layer or causing formation of foam.

The principal object of the present invention is to provide wetting agents for use in the production of photographic layers. Other objects and advantages, some of which are referred to specifically hereinafter will be evident to those skilled in the art to which this invention pertains.

The above objects have been achieved by the addition of monofatty acid esters of the saccharose to the casting solutions of the photographic layer. It is suitable to use esterification products of fatty acids which contain between 8 and 18 carbon atoms.

Saccharose which is also called sucrose, is a disaccharide which on hydrolysis yields D-glucose and D- fructose in equal amounts.

Esterification products with short chain fatty acids or with longer chain fatty acids as well as double esterified products are less suitable.

Preferred are saturated fatty acids such as: caprylic acid, pelargonic acid, capric acid, undecylic acid, lauric acid, tridecoic acid, myristic acid, pentadecanoic acid, or palmitic acid.

Particular suitability exhibit saccharose derivatives which are esterified with acids of a chain length of 10-14 C-atoms, more particularly lauric acid.

In the temperature range employed, the solubility rapidly decreases with increasing number of carbon atoms in the fatty acid. Solutions of saccharose mono-fatty acid derivatives in water foam less vigorously than, for ex- Patented June 23, 1970 ample, aqueous saponine solutions of the same concentration.

Gelatine-containing caustic solutions having a content of saccharose mono-fatty acid derivatives can be applied very uniformly even in relatively thin layers. The excellent effect of these substances is partly due to their ability to emulsify contaminations such as dirt, oils and fats.

The gelatine-containing casting solutions may contain the saccharose derivatives in quantities of 0.1 to 5 g. per liter of solution ready to be cast. The preferred range is about 0.2 to 2 g. This corresponds to an amount in the final dried layer of about 0.04 to 0.4 g. per square meter.

The products are advantageously added in the form of aqueous solutions which contain about 4% wetting agent. The casting solutions may contain the usual other additives such as stabilisers, sensitisers, color couplers, hardening agents, etc.

The photographic properties of the layers are not impaired by the saccharose fatty acid derivatives, even on prolonged storage.

The preparation of saccharose mono-fatty acid esters has been described by York, Finchler, Osipow and Snell, I. Am. Oil. Chem. Soc. 33, 424-426 (1956) (see also Chem. Abstr. 1957, 51, 4958g and C. A. Rhodes, Chem. Prod. Chem. News 21 (1959) 9, 320-323).

It is possible, by ester interchange of fatty acid esters or fatty acid methyl esters with saccharose using a catalyst such as an alkali metal carbonate in a suitable solvent like dimethylformamide, provided certain reaction conditions are observed and a suitable method for working up is employed, to obtain technically pure saccharose mono-fatty acid esters which are practically free from polyesterified saccharose and contain only a small amount of unreacted saccharose. The fatty acid portion is probably present mainly in the 6-position of the glycose part of the disaccharide.

Another possible method of preparing mono-fatty acid saccharates consists in reacting polyfatty acid saccharates with disaccharide. However, the products obtained by this method are not so pure as those obtained by the aforementioned process.

As non-ionogenic wetting agents, the wetting action of the saccharose derivatives is independent of the pH of the solution to be cast. The saccharose esters are sufficiently resistant to saponification for photographic t chniques and compatible with anion-active and with cationactive as well as with non-ionogenic wetting agents. Their use in gelatine-containing solutions makes it possible to increase the speed of application and hence improve the output of casting machines. Further gelatine-containing layers which contain these wetting agents can easily be coated with a further layer shortly after solidification and whilst they are still moist. This further layer may also contain saccharose mono-fatty acid esters.

Another surprising advantage of the saccharose esters is that photographic layers containing these substances in sufficient quantity, especially in the uppermost layer, can be worked up quite satisfactorily using strongly foaming developers. The mechanical development of photographic materials is in practice frequently carried out in apparatus through which a powerful stream of gas is intermittently blown to effect thorough mixing, whereby a very stable foam is usually formed, particularly in the case of developers that have already been used. On slowly introducing photographic materials, the foam bubbles adhere firm 1y to the surface of the film material, with the result that a large number of undeveloped or insufiiciently developed areas occur.

EXAMPLE 1 A 6% gelatine solution without wetting agent, which has been colored by antihalo dyestuffs, is applied to a film support. For comparison, a layer of the same gelatin solution but containing in addition 0.2 g. of saccharose monolaurate per liter is prepared.

To test the effectiveness of the saccharose derivatives, a gelatine solution of the same composition is contaminated with a few drops of machine oil, and after thorough mixing some of it is applied to a film support under the same conditions, again without the addition of Wetting agent. The remaining gelatin solution contaminated with oil is treated with various quantities of a 4% aqueous solution of saccharose monolaurate, mixed thoroughly and also applied to a film support. After drying the layers, the defective areas are counted on a surface of 0.137 square meter.

The results are summarised in the following table:

saccharose mono- Similar results are obtained with mono-fatty acid esters of saccharose with myristic acid or caprylic acid.

EXAMPLE 2 A panchromatically sensitized, highly sensitive iodine bromide emulsion with about g. silver per kg. casting emulsion and about 6 mols percent iodide, which contains saponine as wetting agent in addition to the usual additives such as stabilisers, hardening agents and preserving agents, is cast onto a film support. After solidification but before drying, a 2% gelatin solution for a protective layer which contains 1.6 g. saccharose monolaurate per liter is applied to this emulsion layer.

A very uniform protective layer is obtained. When an exposed material formed as above is developed in a developer which strongly foams by the addition of saponine and by blowing air through it, pictures are obtained which have no insufiiciently developed areas. If saponine or other wetting agents, e.g., alkyl sulphonic acid ester, are used instead of the saccharose monolaurate in the protective layer, and the same method is used for working up, a negative full or circular, empty or feebly developed patches due to the adhesion of air bubbles is obtained.

Sensitivity, gradation and fogging were not influenced by the saccharose monolaurate. The stability on storage was excellent.

EXAMPLE 3 The emulsion described in Example 2 is treated, instead of with saponine, with a mixture of this wetting agent and 1.0 g. saccharose monolaurate, both in the form of 4% aqueous solutions. The application of emulsion on a film support is free of defective areas. The protective layer described in Example 2 is applied to the solidified but not yet dry emulsion layer. Even at high casting speeds, very uniform layers are obtained with this emulsion.

The development in a strongly foaming developer was faultless. Sensitivity, gradation and fogging were not influenced by the new wetting agent.

Stability on storage was good, as before.

EXAMPLE 4 1.6 g. of saccharose monolaurate as Wetting agent is added per liter of casting emulsion to an unsensitized positive Cine emulsion. The emulsion contained 2.8% by weight of silver bromide, corresponding to 16 g. of silver EXAMPLE 5 A casting solution of an emulsion for color reversal films with a cyan color coupler being diffusion resistant contained as wetting agent a mixture of 0.36 g. of an alkylene succinic acid ester and 0.27 g. saccharose monolaurate (used as 4% solution) per liter. This emulsion was applied onto a film support and on this, at the same stage of the operation, a gelatine protective layer was applied which consists of an approximately 1.2% gelatin solution containing about 0.4 g. per liter of the aforesaid alkylene succinic acid ester as wetting agent.

The uniformity of the emulsion casting and its wettability by the gelatin protective layer are achieved by the addition of saccharose monolaurate to the emulsion layer. While there have been pointed out certain preferred embodiments of the invention, the same is not limited to the foregoing examples or to the specific details given therein, but are capable of numerous variations and embodiments as to the emulsions or gelatin layers, proportions or casting conditions employed.

We claim:

1. A photographic element comprising a support, at least one layer comprising a hydrophilic colloid and a sucrose ester of an aliphatic monocarboxylic acid having at least 8 carbon atoms.

2. A silver halide photographic emulsion containing a sucrose ester of a fatty acid having at least 8 carbon atoms.

3. A light-sensitive photographic material containing at least one silver halide gelatin emulsion layer, not less than one gelatin layer thereof containing an eifective amount of a mono-ester of saccharose with a fatty acid of 818 carbon atoms.

4. Photographic material of claim 3 wherein the gelatin layer contains about .04-.4 g. saccharose mono ester per square meter of material.

5. Photographis material of claim 3 wherein the gelatin layer contains saccharose monolaurate.

6. Photographic material of claim 3 wherein the gelatin layer containing the mono ester of saccharose with the fatty acid is the uppermost layer.

7. Light-sensitive photographic silver halide gelatin emulsion which contains per liter of casting solution 20-80 g. gelatin and 0.2-2 g. of a mono ester of saccharose with a fatty acid having 8-18 carbon atoms.

References Cited UNITED STATES PATENTS 4/1938 Harris 16791 1/1962 Lewis 16791 OTHER REFERENCES I. TRAVIS BROWN, Primary Examiner US. Cl. X.R. l06-126 

